Cutting blade



Aug. 9, 1932;.v

M. MAAG ET AL CUTTING BLADE Original Filed NOV. 10, 1928 1710614 22725 WAX 44 74 44 Ill-(Ill Patented Aug. 9, 1932 UNITED STATES, PATENT OFFICE j MAX ltIAiG, OF SCHWAMENDINGEN, NEAR ZURICH, SWITZERLAND, AND ROBERT SAL- OMON, OF VAL'DOIE, NEAR BELFOR'I, FRANCE, DEEIACHINES A AFFUTER, F PAR-IS, FRANCE Corrine BLADE Origin-a1 application filed. November 10, 1928, Serial No. 3 18 327. iDivided and this application filed.

' October 31, 1931. Serial No. 572 ,396.' I

This invention relates to cutting blades and particularly to improvements in cutting edges of thin flexible razor blades.

An object of the present invention is to provide an improved cutting edge for blades such as razor blades, the intersecting surfaces of which are substantially fiat or concaved directly up to the edge, the contour being continuous up to the cutting edge, and there being no portion of the intersecting surfaces forming the cutting edge that are convexly curved.

A feature of importance which enables the above object of the invention to be accomplished is that the cutting surfaces of the blade while being ground are maintained against any distortion due to pressure of the grinding element and are accurately ground in fiat or slightly concaved form, the finishing operation applied to the edgesserving to smooth and polish the surfaces immediately adjacent the cutting edge while preserving the contour to which these surfaces have been ground. r

lVith these and other objects in view our invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawing.

In the accompanying drawing annexed hereto and forming a part of this specification, we have shown our invention embodied in a thin, flexible, double-edged razor blade, but it will be understood that the invention can be otherwise embodied and that the drawing is not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied upon for that purpose.

In the drawing:

Figure 1 is a conventional form of cutting blade which may have cutting edges thereon of the type described and claimed'in this application. r

Fig. 2 is a cross sectional view, greatly magnified, of a'small portion of the present improved blade adjacent its edge after being ground.

Fig. 3 is a view similar to Fig. 2 showing portions adjacent an edge of the present improved type of blade after having been completely finished.

Fig. t is a diagrammatic'view of a device by means of which theim'provededges may.

be ground,

Figl 5 isa cross-sectional view of a portion of the improved cutting edge greatly magnified and shown superposed over a corresponding portion of Ja'conventional blade of the prior art, both cutting edges being shown immediately after the grinding operation.

Fig. 6 is a view similar to Fig. 5 of a portion of applicants cuttingedge after grinding and shown superposed over a similar portion of a prior art blade, both cutting edges being shownready for the final finishing operation, and

Fig. 7 is a View, magnified similarly to Fig,

2, and showing a finished blade of conventional or priorart forin. In the above drawing we have shown a preferred'form of the invention and a method by which it may be ground, but it will be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention. i Briefly and in its broadest aspect our invention may include a blade having its cutting surfaces characterized by being'fiat or concave as distinguished from convex imme diately adjacent the cutting edge, the contours of the cutting surfaces as ground being preserved in the finished blade.

Referring more in detail tothe figures of the drawing, We show a blade 10 of conventional thin and flexible form which may have its'cutting edges formed according to the present invention. The process and device preferably madeuseofin the production of the present cutting edges. are shown in our copending applications 318,327 and 417,051

AS SIGNORS TO SOCIETE DETUIDES' filed November 10,1928 and December 28, 7

i929 respectively. This present application forms a division of applic'ation318,327.

The surfaces forming the cutting edge of the bladelO are ground to the form shown by the lines 11 11, the method of grinding one of these surfacesbeing shown-diagrammatically in Fig. 41. -The blade 10 during the grinding operation is Supported by a rigid member 12 closely fitting the side opposite that being ground and extending up to and beyond 'the cutting edge. The'wheel 13 effecting the grinding is advanced against theblade 10 While thus supported and ingrindingfthe surfaceof the bladelQopposite that supported by-the surface'of supportinginem' ber 12 cuts away a small portion of the support 12 closely'adj acent the cutting edge being formed. By being thus supported-uptol its cutting edge hile being ground the cutting e'dge'i's formed asshown,"gg-eatlymagnt fled, in Fig. 2, the surfaces forming the cut: ting edge beingundistorted during the grind; ing operation, due toits being completely supported and consequently retaining a slightly concave form Th fininn g-opemnga of the blade 10, usually honing and'stroppmg, re

quires only to smooth and polish the areas of the cutting surfaces 11 immediatel along the edge This reduced amount. oijf lnis'hing operat1on required is due to the absence of a fin edge 14 as shown in Fig; 5 formed along the ground edge bythe conventional grinding operation and as indicatedin Fig. 5.

Ln finishing blades of the prior art .type such as shown by theouter contours 16 in Figs. 5and 6, after the grinding operation the firsteifectisto break away the .fin extension 14: formed during grinding, leaving a rounded :blunt edge as shown in the outer contour in Fig. 6. Thexiinisliingof these prior art.

blades therefore must be continued until the bluntedxedge, the thickness ofwhich corresponds to the thickness of the fin 1&- is sharpened to a keen edge. In accomplishing this finishing'of a relatively blunt edgeas by honing the effect is to form convexsurfaces adjacent the edges as indicated in 7 in. magnified form similar to Figs. 5 andfi It is primarily in the elimination of this convex. form of the cutting surfaces immediately adjacent the cutting edge that characterizeslthe presentimproved blade.

The thickness of the fin 14 formed by the conventional grinding and shown in magnisfi'ed form in llig. 5 is a definite and material amount and represents the Width of the blunttion.

form, the intersecting angle being slightly but not materially increased. The continuously curved form of the cutting surfaces formed by the grinding operation are maintained Without distortion during the finishing'o'pera- What we claim is 1. As an article of manufacture, a blade having a cutting edge having slightly 'concave marginal faces,-characterized by the fact that said faces are substantially flat in the immediate proximity of said edge as distinguished from convexdue to the absolute absence of any deformationsoccurring adjacent the edge during the edge forming and finishing treatment;

2. As an article of manufacture, a} blad having a cutting edge having two intersect-i characterized by the fact that at leastone of said faces is of uniform concave form throughout its area adjacent said edge.

3. As an article of manufacture," a thin flexible razor blade having a cutting edge having two intersecting ground faces inmg ground faces inclined to each other and clined to each other and characterizedby the ROBERT SALOMON.

ed'edge shown in Fi'g fi. This thickness must, l be .eliminat'edand determines the amount of finishing such as honing or stroppingnecessary to give the blade a sharp edge. Byfor-mingthecutting surfaces oftheimproved edge by the grinding operation as represented diagrammaticallynin Fig, l Wl-ierein no fin ,is produced and thus eliminating the necessity offinishing a blunt edge, hat finishing is necessary for the improved blades amounts 7 only to smoothing the surfaces to-eliminate the scratches formed in grinding by the abrasive material used. The edge-as indicated in Eig remains. after with .itscutting surfaces substantially ,unj changed,; retaining 'l their substantially flat, or slightly concave 

